There were 663 million people without access to safe drinking water in 2015, according to the United Nations and World Health Organization. Many of those going without are from low-income households in cities across the global south. Jenna Davis, associate professor and Higgins-Magid senior fellow at the Woods Institute of the Environment at Stanford University, says this problem is an economic burden and strain on development.

“By reducing exposure to fecal pathogens, you not only help reduce child mortality associated with those illnesses, but we’re starting to understand that the health and productivity effects can actually include stunting and impaired cognitive development,” Davis says, in an interview for the Cities Research Seminar Series. “So if you think about the long-term effects of removing those fecal pathogens from the environment, you could actually be talking about measurable impacts on the economy of cities and countries.”

Improving urban water and sanitation, however, is no simple task.

Focusing Further Upstream for Sanitation

In the past, practitioners have focused on “point-of-use” approaches, which try to empower households to manage their own water quality through chlorine products, filters and similar user-driven technological solutions.

Davis says that these can be effective, if used correctly and consistently, “but it’s a pretty tall order to ask a low-income household to consistently, day-in and day-out, use those technologies.” Additionally, in a neighborhood with poor sanitation services, the first household to improve its condition bears the cost of the improvement but creates benefits for its neighbors. This creates a disincentive to act, as some seek to freeride on the public benefit produced by others.

“An alternative approach we’ve been thinking about is to move up one scale and think about intervening at a shared water point, like a public tap or a hand pump,” Davis says. Especially for waste management, “in most low-income countries, responsibility for construction, financing, operation and maintenance all fall to the end users.” That can be an overwhelming task for low-income households in the absence of government support. “We really need to be thinking about what is the proper role of government in subsidizing.”

Better Pricing Schemes to Increase Supply

When it comes to the supply side, Davis says practitioners should carefully consider how different pricing structures for water impact households at different income levels.

For example, a common tariff structure is the increasing block tariff, in which households pay more per unit volume of water the more they use. While this might make sense initially, it turns out that low-income households end up paying the most because a single tap is often shared among several households.

“This is not a new insight,” says Davis, “we’ve known about this for a while. But it’s been slow to take root in terms of tariff reform for cities of the global south.”

One city that is experimenting successfully with water supply reform is Maputo, a city of 1.7 million and the capital of Mozambique. The city recently decriminalized the resale of water between households, allowing individuals with private water taps to sell or give water to their neighbors without threat of prosecution.

“This decision was based on some really good research that demonstrated that this type of service provides time savings,” Davis says. “It’s not exploitative, in terms of the monetary costs and actually could represent, because of volumetric pricing at the utility level…a costless expansion of the pipe network to the urban poor.”

Policy solutions like subsidizing community sanitation projects, adjusting tariff structures, and allowing water resale, can have significant impacts for the urban poor, and Davis is optimistic about the prospects for change. “I think in general this is feasible, if you can muster the political will to do it, because there is relatively high demand even among low-income households for safe and reliable water supply services.”

Alex Rogala is a former editor of TheCityFix and currently a master’s student in urban planning at the Harvard Graduate School of Design.